Isuzu Trooper (2000 year). Manual - part 303

6E–341

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC)

P0453 Fuel Tank Pressure Sensor (Vapor Pressure Sensor) High Voltage

D06RY00178

Circuit Description

The powertrain control module (PCM) monitors fuel tank
pressure sensor (Vapor pressure sensor) of the
Enhanced Evapo system. When the tank pressure output
indicates high voltage , PCM will set DTC P0453.

Conditions for Setting the DTC

Tank sensor output is more than 4.9 volts for 12.5 sec.

100 test failures within a 200 tests.

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) as soon as failure detected.

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in Failure
Records data.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0453 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

Info function or by disconnecting the PCM battery feed.

Diagnostic Aids

Check for the following conditions:

Open circuit of sensor ground line – Inspect wiring
harness from PCM to the sensor. The PCM turns
P0453, and P0108 at the same time.

Open circuit or short circuit to 5 volt reference line –
Inspect wiring harness from PCM to the sensor. The
PCM turns P0453 and P0108 at the same time.

Tank fuel pressure sensor malfunction may cause
P0453.

Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.

6E–342

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0453 – Fuel Tank Pressure Sensor High Voltage

Step

Action

Value(s)

Yes

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to

Step 2

Go to

OBD

System

Check

1. Ignition “ON,” engine “OFF”, review and record

Tech 2 Failure Records Data.

2. Operate the vehicle within Failure Records

conditions as noted.

3. Using a Tech 2, monitor “DTC” info for DTC P0453

until the DTC P0453 test runs. Note the result.

Does the Tech 2 indicates DTC P0452 or P0452/P0107
failed this ignition?

—

P0453/P0108

turn on

Go to

Step 3

P0452 turns on

Go to

Step 6

Refer to

Diagnostic

Aids

1. Ignition “OFF”.
2. Disconnect connector at the PCM.
3. Ignition “ON”.
4. At the PCM connector, measure voltage with a

DVM at F54 and S37 terminals.

Was the voltage in range of voltage?

4–6 V

Go to

Step 4

Go to

Step 10

1. Ignition “OFF”.
2. Connect the PCM connector to the PCM.
3. Disconnect sensor harness at fuel pressure sensor.

Measure voltage with a DVM at the end of the tank
pressure wiring between 5 V reference terminal and
sensor ground terminal.

Was the voltage within range?

4–6 V

For P0453 go

Step 6 and

for P0108, go

to diagnosis

section.

Go to

Step 5

1. Locate open wiring of ground line from the PCM to

fuel tank pressure sensor.

2. Repair wiring harness.

Is the action complete?

—

Verify repair

—

1. Ignition “ON”.
2. At the PCM connector, backprove with a DVM at the

sensor output for the voltage.

Was voltage within the range?

More than

4.9 V

Go to

Step 7

Go to

Step 10

At the sensor output terminal, backprobe with a DVM at
the sensor output.

Was the voltage within range?

More than

4.9 V

Go to

Step 9

Go to

Step 8

1. Locate open circuit or short circuit to ground line.
2. Repair the harness.

Is the action complete?

—

Verify repair

—

Replace the tank pressure sensor.

Is the action complete?

—

Verify repair

—

6E–343

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0453 – Fuel Tank Pressure Sensor High Voltage

(Cont'd)

Step

Yes

Value(s)

Action

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed. Refer to

On-Vehicle Service in

Powertrain Control Module and Sensors for
procedures.

And also refer to latest Service Bulletin.

Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.

Is the action complete?

—

Verify repair

—

6E–344

TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0456 EVAP Very Small Leak

D06RY00128

Circuit Description

The evaporative system includes the following
components:

Fuel tank

EVAP canister vent solenoid

Fuel tank pressure sensor

Vapor lines

Fuel cap

Evaporative emissions canister

Purge lines

EVAP canister purge solenoid

The evaporative leak detection diagnostic strategy
is based on applying vacuum to the EVAP
systemand monitoring vacuum decay. The
powertrain control module(PCM)monitors vacuum
level via the fuel tank presuure sensor input .At an
appropriate time, the EVAP canister purge
solenoid and the EVAP canister vent solenoid are
turned “ON,” allowing engine vacuum to draw a
very small on the entire evaporative emissions
system. After the desired vacuum level has been
achieved, the EVAP canister purge solenoid is
turned “OFF”, sealing the system. A leak is
detected by monitoring for a decrease in vacuum
level over a given time period, all other variables
remaining constant.

A very small leak in the system will cause DTC
P0456 to be set.

Conditions for setting the DTC

No MAP DTC’s set.

No TPS DTC’s set.

No IAT DTC’s set.

No ECT DTC’s set.

No tank pressure sensor DTC’s set.

Baro is more than 70KPa.

A vacuum decay condition, indicating a very small leak,
is detected during the diagnostic test.

Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) after the second consecutive trip in which the
fault is detected.

The PCM will store condition which were present when
the DTC was set as Freeze Frame and in the Failure
Records data.

Warm up cycles have occurred without a fault.

Conditions for Clearing the MIL/DTC

The PCM will turn the MIL “OFF” on the third
consecutive trip cycle during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0456 will clear after 40 cosecutive trip
cycle during which the warm up cycles have occurred
without a fault.

DTC P0456 can be cleared using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

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